New designs for third and fourth generation (3G and 4G) capable wireless devices and networks enable users to transmit/receive simultaneous IP data streams to/from multiple destinations or web sites and thereby multitask among different applications. For instance, a user might choose to hold a VoIP phone conversation while simultaneously surfing web pages with a browser application and receiving streaming video using a third application. All of these tasks may be performed on a single channel of an air interface access technology in protocols such as LTE (Long Term Evolution), HRPD (High Rate Packet Data), WiFi, WiMax, etc.
Simultaneous operation of the tasks may be achieved via packet data transmission and multiplexing which essentially implements a time division sharing of the channel among the applications. In an alternative approach, multiple tasks may be split up among two or more of the access technologies for simultaneous access by establishing a different mobility session for each technology.
The two most commonly used mobile IP protocols currently in use are known as Client Mobile IP (CMIP) and Proxy Mobile IP (PMIP). Both of these protocols are grounded on the concepts of home networks, home addressing, and IP tunnels. The protocols allow for location-independent routing of IP packets on the Internet. The earlier protocol, CMIP (also called MIP), has been revised several times; a recent version is set forth in an Internet Engineering Task Force (IETF) document RFC 3775 entitled “Mobility Support in IPv6”, by Johnson et al., June 2004. PMIP is described in IETF document RFC 5213 entitled “Proxy Mobile IPv6”, by Gundavelli et al., August 2008.
In the operation of CMIP and PMIP, a large wireless network is subdivided into zones, where each zone may be designated as a home network for a number of access terminals (cell phones with Internet capability, laptops, PDA's, etc.). Thus, each access terminal that is permitted to access the large network is assigned to a home network, which is typically the zone in which the subscriber of the access terminal resides. The access terminal is also called a host or a mobile node. The access terminal communicates via the network with correspondent nodes (CNs) attached to the Internet; these CNs may be web sites, other access terminals, fixed location computers, etc.
The home network of a mobile node is the network within which the mobile node receives its identifying IP address. A mobile node is always expected to be addressable at its home address, whether it is currently attached to its home link or is away from home. The home network includes an entity responsible for maintaining this home address. In CMIP this entity is called a home agent; in PMIP it is called a local mobility anchor (LMA). A home agent or LMA is a router which tunnels packets for delivery to the mobile node when it is away from home. The packets are tunneled to an access gateway of an access network in another zone at a “care-of address” for the mobile node. In CMIP this access gateway is called a foreign agent or an access router (in earlier and later versions, respectively); in PMIP it is called a mobility access gateway (MAG).
Despite the recent technological advances that have made mobile IP operation not only possible but ubiquitous, the goal of enhancing the user experience is never ending. To this end, efforts continue to improve quality by reducing the occurrence of dropped calls, interruptions, delays, interference, etc., as well as to optimize system resources, add functionality and expand services.